Re: UID Limit

2002-05-23 Thread Peter Pentchev

On Wed, May 22, 2002 at 04:53:37PM -0700, Darren Pilgrim wrote:
 Peter Pentchev wrote:
  
  On Wed, May 22, 2002 at 04:27:12PM +0100, Jamie Heckford wrote:
   Hi,
  
   I was wondering if anyone would be able to tell me what the limit is on a
   UID? Ie what is the highest integer it can go up to.
  
   I suppose as well some applications have different values.. or am I
   completly wrong :)
  
  The functions that deal with user ID's take a parameter of type uid_t.
  The uid_t type is defined in sys/types.h as u_int32_t.  Hence, at least
  theoretically, FreeBSD supports uid's in the range 0 to 4G-1.
 
 It supports them that high, yes, but I believe they wrap at 9.

I believe you are thinking of pid's (process ID's), not uid's (user ID's).

G'luck,
Peter

-- 
Peter Pentchev  [EMAIL PROTECTED][EMAIL PROTECTED]
PGP key:http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint FDBA FD79 C26F 3C51 C95E  DF9E ED18 B68D 1619 4553
This sentence contradicts itself - or rather - well, no, actually it doesn't!



msg34568/pgp0.pgp
Description: PGP signature


Re: UID Limit

2002-05-23 Thread Darren Pilgrim

Peter Pentchev wrote:
 I believe you are thinking of pid's (process ID's), not uid's (user ID's).

Yes, you're right.  Serves me for trying to do email after a long
night of hacking at perverse bit-twiddling scripts.

To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-hackers in the body of the message



UID Limit

2002-05-22 Thread Jamie Heckford

Hi,

I was wondering if anyone would be able to tell me what the limit is on a
UID? Ie what is the highest integer it can go up to.

I suppose as well some applications have different values.. or am I
completly wrong :)

Thanks

Jamie


To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-hackers in the body of the message



Re: UID Limit

2002-05-22 Thread Peter Pentchev

On Wed, May 22, 2002 at 04:27:12PM +0100, Jamie Heckford wrote:
 Hi,
 
 I was wondering if anyone would be able to tell me what the limit is on a
 UID? Ie what is the highest integer it can go up to.
 
 I suppose as well some applications have different values.. or am I
 completly wrong :)

The functions that deal with user ID's take a parameter of type uid_t.
The uid_t type is defined in sys/types.h as u_int32_t.  Hence, at least
theoretically, FreeBSD supports uid's in the range 0 to 4G-1.

However, if you decide to go above 64K-1, you may hit various limitations.
NFS and NIS (YellowPages), for example, will not be too happy about uid's
that big, IIRC.  There might be other programs which assume 16-bit uid's,
although I cannot think of any at the moment.

After 64K-1, the next roadblock is 2G-1, a.k.a. INT_MAX.  This will become
a problem as soon as some program tries to store an uid_t value into
a plain, signed int variable - the value will either turn negative, or
be truncated to 2G-1, and much fun will ensue.  It is not too common for
a program to misuse an uid in this kind, but it is for a gid - there are
many programs, including some in the FreeBSD base system, which use 'int'
instead of 'gid_t', simply because it's defined that way in gid.h.
The 'usual' user creation utilities try to keep the gid the same as the uid,
so if you create a user with an uid  2G-1, your gid experience might be..
mm.. interesting.

So, to sum it all up - there are no problems, except where there are :)

G'luck,
Peter

-- 
Peter Pentchev  [EMAIL PROTECTED][EMAIL PROTECTED]
PGP key:http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint FDBA FD79 C26F 3C51 C95E  DF9E ED18 B68D 1619 4553
If the meanings of 'true' and 'false' were switched, then this sentence wouldn't be 
false.



msg34559/pgp0.pgp
Description: PGP signature


Re: UID Limit

2002-05-22 Thread Darren Pilgrim

Peter Pentchev wrote:
 
 On Wed, May 22, 2002 at 04:27:12PM +0100, Jamie Heckford wrote:
  Hi,
 
  I was wondering if anyone would be able to tell me what the limit is on a
  UID? Ie what is the highest integer it can go up to.
 
  I suppose as well some applications have different values.. or am I
  completly wrong :)
 
 The functions that deal with user ID's take a parameter of type uid_t.
 The uid_t type is defined in sys/types.h as u_int32_t.  Hence, at least
 theoretically, FreeBSD supports uid's in the range 0 to 4G-1.

It supports them that high, yes, but I believe they wrap at 9.

To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-hackers in the body of the message